ZD2 not syncing well with MAC

We are running ZD 2 on iMacs and Macbook Pros (MAC OS X 10.6.4.) and are experiencing sync problems. Mail does not always appear in the inbox unless one clicks either the inbox or refresh after which they appear in a batch.

After a sleep mode, it often takes up to 10 minutes to sync and sometimes it does not sync at all until ZD 2 is relaunched.

Both issues are making ZD 2 unreliable and cumbersome to use. Is this a known issue and or does a remedy exist?

We have re-installed ZD 2 several times, but the issue remains. ZD1 did sync far better.